Multiple stage modulation projector display systems having efficient light utilization

ABSTRACT

Dual or multi-modulation display systems comprising a first modulator and a second modulator are disclosed. The first modulator may comprise a plurality of analog mirrors (e.g. MEMS array) and the second modulator may comprise a plurality of mirrors (e.g., DMD array). The display system may further comprise a controller that sends control signals to the first and second modulator. The display system may render highlight features within a projected image by affecting a time multiplexing scheme. In one embodiment, the first modulator may be switched on a sub-frame basis such that a desired proportion of the available light may be focused or directed onto the second modulator to form the highlight feature on a sub-frame rendering basis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 15/880,239, filed Jan. 25, 2018, which is aContinuation Application of U.S. patent application Ser. No. 15/358,998,filed Nov. 22, 2016, now U.S. Pat. No. 9,918,052, issued on Mar. 13,2018, which is a Continuation Application of U.S. patent applicationSer. No. 14/696,918 filed on Apr. 27, 2015, now U.S. Pat. No. 9,531,982,issued Dec. 27, 2016, which is a Continuation Application of U.S. patentapplication Ser. No. 14/300,585 filed on Jun. 10, 2014, now U.S. Pat.No. 9,049,413, issued on Jun. 2, 2015, which claims the benefit ofpriority to U.S. Provisional Patent Application No. 61/860,203 filed onJul. 30, 2013 entitled, “Multiple Stage Modulation Projector DisplaySystems Having Efficient Light Utilization” which are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to displays systems and, moreparticularly, to dual or multi-stage modulation projection displaysystems.

BACKGROUND

In a conventional projector system, there is typically a single lightsource that illuminates a screen with an image that is modulated by someoptical system within the projector. When there is an image to beprojected that has a “highlight” (that is, a region of highbrightness—e.g., a specular reflection off of a surface in the image,direct sunlight, a luminant object, one region that is substantiallymore luminant than other regions or the like), then the highlight wouldhave the same luminance level as the “full” screen. In that case, thelight coming through the projector would have to be fully ON for theentire screen and the projector system would have to “throw away” lightthat is not a part of the highlight. This may not tend to be themost-efficient use of the light source.

SUMMARY

Several embodiments of display systems and methods of their manufactureand use are herein disclosed.

Dual or multi-modulation display systems comprising a first modulatorand a second modulator are disclosed. The first modulator may comprise aplurality of analog mirrors (e.g. MEMS array) and the second modulatormay comprise a plurality of mirrors (e.g., DMD array). The displaysystem may further comprise a controller that sends control signals tothe first and second modulator. The display system may render highlightfeatures within a projected image by affecting a time multiplexingscheme. In one embodiment, the first modulator may be switched on asub-frame basis such that a desired proportion of the available lightmay be focused or directed onto the second modulator to form thehighlight feature on a sub-frame rendering basis.

In one embodiment, a multi-modulation projector display system, saiddisplay system comprising: a light source; a controller; a firstmodulator, said first modulator being illuminated by said light sourceand said first modulator comprising a plurality of analog mirrors tomodulate light from the light source; a second modulator, said secondmodulator being illuminated by light from said first modulator andcapable of modulating light from said first modulator, and said secondmodulator comprising a plurality of mirrors; said controller furthercomprising: a processor; a memory, said memory associated with saidprocessor and said memory further comprising processor-readableinstructions, such that when said processor reads the processor-readableinstructions, causes the processor to perform the followinginstructions: receiving image data, said image data comprising at leastone highlight feature; sending control signals to said first modulatorsuch that said first modulator may allocate a desired proportion of thelight from said light source onto said second modulator to form saidhighlight feature; and sending control signals to said second modulatorsuch that said desired proportion of the light from said light source ismodulated to form said highlight feature.

In another embodiment, a processor-implemented method for renderinghighlight features within video data stream, said video data streambeing projected by a multi-modulation projection display system, saiddisplay system comprising a first modulator, said first modulator, saidfirst modulator comprising a plurality of analog mirrors, a secondmodulator, said second modulator comprising a plurality of mirrors and aprocessor, said processor controlling said first modulator and saidsecond modulator, the method comprising: receiving image data, saidimage data comprising at least one highlight feature; sending controlsignals to said first modulator such that said first modulator mayallocate a desired proportion of the light from said light source ontosaid second modulator to form said highlight feature; and sendingcontrol signals to said second modulator such that said desiredproportion of the light from said light source is modulated to form saidhighlight feature.

Other features and advantages of the present system are presented belowin the Detailed Description when read in connection with the drawingspresented within this application.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered illustrative rather than restrictive.

FIG. 1 is one embodiment of a dual modulation projector display systemthat may be suitable for the systems, methods and techniques of thepresent application disclosed herein.

FIGS. 2A and 2B depict a high level schematic description ofilluminating a highlight section within a given projected image as madein accordance with the principles of the present application.

FIGS. 3A, 3B and 3C depict one embodiment of a time divisionmultiplexing scheme as made in accordance with the principles of thepresent application.

FIG. 3D is one embodiment of a control method for affecting therendering of highlight features within a projected image by amulti-modulator display system.

FIGS. 4 and 5 depict two embodiments of a multi-modulator projectorsystem as made in accordance with the principles of the presentapplication.

FIG. 6 depicts one high-level diagram of switching scheme that matchesthe bit-sequence repeating pattern.

DETAILED DESCRIPTION

Throughout the following description, specific details are set forth inorder to provide a more thorough understanding to persons skilled in theart. However, well known elements may not have been shown or describedin detail to avoid unnecessarily obscuring the disclosure. Accordingly,the description and drawings are to be regarded in an illustrative,rather than a restrictive, sense.

As utilized herein, terms “component,” “system,” “interface,”“controller” and the like are intended to refer to a computer-relatedentity, either hardware, software (e.g., in execution), and/or firmware.For example, any of these terms can be a process running on a processor,a processor, an object, an executable, a program, and/or a computer. Byway of illustration, both an application running on a server and theserver can be a component and/or controller. One or morecomponents/controllers can reside within a process and acomponent/controller can be localized on one computer and/or distributedbetween two or more computers.

The claimed subject matter is described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the subject innovation. It may be evident, however,that the claimed subject matter may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form in order to facilitate describing the subjectinnovation.

Introduction

With current digital projector, the full screen and highlight luminancelevels tend to be equal, but this approach also tends to be inefficientfrom the standpoint of light energy considerations.

In many embodiments disclosed herein, novel dual modulator, triplemodulator and other multi-modulator projection display systems andtechniques offer the possibility of putting additional light ontohighlight features on a projected image—as opposed to throwing awayexcess light that is not needed. Many embodiments employ a combinationof a MEMS array as a first (or early) stage modulator that projects anintermediate illumination onto a second (or later) stage DMD modulator.

In another aspect of several embodiments of the present application, anovel time division multiplexing scheme may aid the systems andarchitectures of the novel dual, triple and/or multi-stage modulatorprojector systems. If a frame of image data may be projected in asequence of sub-frames, then highlights may be accommodated in anefficient manner, from the consideration of light energy usage. In otheraspects of several embodiments, advanced bit sequence schemes aredisclosed that may help to affect such time division multiplexingschemes.

Light Efficient Dual-Modulator Projector Embodiments

Dual modulation projector systems have been described in commonly-ownedpatents and patent applications, including:

(1) U.S. Pat. No. 8,125,702 to Ward et al., issued on Feb. 28, 2012 andentitled “SERIAL MODULATION DISPLAY HAVING BINARY LIGHT MODULATIONSTAGE”;

(2) United States Patent Application 20130148037 to Whitehead et al.,published on Jun. 13, 2013 and entitled “PROJECTION DISPLAYS”

-   -   which are hereby incorporated by reference in their entirety.

In many dual, triple, more than 2-modulation (all of which arehereinafter referred to as “multi-modulation”) display systems disclosedherein use beam steering to put light on the modulation chips only whereneeded.

FIG. 1 is one embodiment of a dual modulating projector display system100, comprising two or more digital projectors (as modulators). FIG. 1shows a monochrome display 102 according to this example embodiment.Display 100 comprises a light source 102. Light 104 from light source102 illuminates a first light modulator 106. Light source 102 maycomprise, for example: a laser; a xenon lamp; an array of lasers (e.g.,diodes or otherwise) or other solid-state light emitters; an arc lamp;or the like.

In one embodiment, the first light modulator 106 may comprise aplurality of controllable elements 106 a—e.g., on a fast switchingdevices, such as a MEMS device or the like. As will be described ingreater detail below (and in reference to FIGS. 2A-B and FIGS. 3A-C),elements 106 a may be selected such that they may be steered to reflectlight to a second modulator 110 by a suitable control circuit/controller116. The controller 116 may comprise a processor, a memory incommunication with the processor and such that the memory may compriseinstructions such that the controller may suitably control firstmodulator and second modulator (and other modulators, if they are in thesystem at issue) to perform the highlighting techniques as describedherein.

The set of controllable elements may also comprises a set ofcontrollable analog mirrors—possibly with switching speeds sufficientlyresponsive to provide subframe rendering for processing highlights asdescribed herein. In one embodiment, the switching response time ofelements 106 a may be fast enough—so as to reflect light onto the secondmodulator several times in a given frame of image data. For example,elements 106 a may affect a half frame, third frame, a quarter frame, or1/n frame illumination onto second modulator 110, as desired.

Light from first modulator 106 may pass through an optical system108—which may comprise sufficient optical components to perform adesired point spread function (PSF) of illumination onto secondmodulator 110. Depending on the ratio of elements 106 a in firstmodulator 106 to elements 110 a in second modulator 110, the desired PSFmay vary accordingly. For example, if the first modulator 106 is a MEMSarray and second modulator 110 is a DMD array, a typical MEMS array hasmany less elements 106 a (e.g., range from a few hundred to a fewthousand mirror elements, 100 to 2-3K)—than a DMD array that may be afew million mirror elements thereon (e.g. over 500K mirrors and over).

Second light modulator 110 may be controlled by control circuit 116 (asfirst light modulator 106 may be) and comprise a plurality ofcontrollable elements 110 a. Each controllable element 110 a can becontrolled to select a proportion of the light that is incident on theelement 110 a from first spatial light modulator 106 that is transmittedto a viewing area 114 (through, possibly a second optical system 112).

In some embodiments, second spatial light modulator 110 comprisesoptical reflective or transmissive elements 110 a that can be switchedbetween ON and OFF states, e.g., a DMD device. In such embodiments,second spatial light modulator 110 may be controlled by a controllerthat sets its elements to be ON or OFF.

Transfer optics 108 carries light from first light modulator 106 tosecond light modulator 110. This light is capable of illuminating theentire active area of second light modulator 110 when all elements 106 aof first spatial light modulator 106 are ON. This light could spreadpast the edges of second spatial light modulator 110. Transfer optics108 may blur the light. Transfer optics 108 may be characterized by atransfer function which at least approximates how light issuing from apoint on first spatial light modulator 106 will be spread over secondspatial light modulator 110. The pattern of light incident on secondlight modulator 110 can be estimated or determined from theconfiguration of first modulator 106 (i.e. from which elements 106 a areON and which elements 106 a are OFF) and the transfer function. Asuitable projection lens 112 focuses light from second spatial lightmodulator 110 onto a screen 114 for viewing. Screen 114 may comprise afront-projection screen or a rear-projection screen.

Although the embodiment of FIG. 1 depicts a single light channel, itwill be appreciated that the first and second modulators may bereplicated for each of a series of color channels within the projectorsuch that each color channel includes 2 optically offset reflectivemodulators. The series of color channels may comprise a red channel, agreen channel, and a blue channel. The light source may comprise, forexample, a plurality of colored laser light sources. In one embodiment,the light sources may be modulated either globally (in brightness)and/or spatially (locally) dimmed according to signals (not shown) froma controller (e.g., 116).

The intermediate signals to the second modulator may be, for example,based on a light field simulation comprising a point spread function oflight reflected by the first modulator and the offset. For example, theintermediate signals to the second modulator may be based on a pointspread function of light reflected by the first modulator in eachchannel and the offset in each channel. The offset in the channels maybe the same, or the offset of at least two channels is different and theintermediate signals to second modulator in each channel is based on atleast one of the offset and differences in offset between channels.

Light Efficient Operation Embodiments

In one embodiment of the present application, the dual modulationprojector system of FIG. 1 may be employed to affect an efficient lightusage. FIGS. 2A through 2C depict one embodiment in which the dualmodulation system of FIG. 1 may be capable of providing illumination ofhighlights within an image in an efficient manner from the standpoint oflight energy.

FIG. 2A depicts merely a portion 200 of the display system 100. Mainlight beam 202 illuminates the first modulator 204—which may be anysuitably fast switching device, such as a MEMS device or some set offast switching reflective and/or transmissive elements. As may be seen,first modulator 204 is able to steer light beam 202 onto the elements ofthe second modulator 208.

The illumination, in FIG. 2A, would be sufficient to illuminate asubstantially full image on a projection screen 214—passed, possibly,through sufficient projector optics 212. As may also be seen, an imageof a crown—which may comprise a lower portion 220 a and an upper portion220 b—is shown on the projector screen. In this example, suppose thatthe top portion of the crown is to be displayed as a highlight (i.e., atsubstantially full illumination of the display system). Suppose furtherthat the lower portion of the crown is not to be displayed at fullillumination—thus, further highlighting the top portion of the crown.

As is known, one approach to obtaining bright high contrast images(e.g., with highlights) using such a dual modulation projector may be tohave the full screen and highlight luminance levels are equal—andprovide the necessary modulation via, e.g., a pulse width modulation.However, this approach may not be the most efficient—as typically pulsewidth modulation employs a constant light for the entire frame period.Thus, the modulators need to throw away a certain amount of light energyduring the frame period.

FIG. 2B depicts one embodiment of the present application may supplysuch a highlight to portion 220 b—without undue waste of the lightenergy. As may be seen, the active elements of first modulator 204 maybe switched for a first time period (possibly, for less than a fullframe)—such that more light energy is focused onto a portion of thesecond modulator that directly forms the portion of the highlight 220b′. For this first period of time, more of a relative amount of lightfrom the main beam 202 illuminates the highlight.

FIGS. 3A through 3C depict the sequence of illumination over the courseof three time periods. FIGS. 3A and 3B show the same image illuminationof FIGS. 2A and 2B, respectively, over a first and second time period(T1 and T2). In a third period of time, T3, FIG. 3C may show the sameimage as in FIG. 3A.

This exemplary set of figures (FIGS. 3A through 3C) demonstrate ascheme—similar to time division multiplexing—in which a portion of animage may be highlighted, without throwing away excess light energy. Infact, the amount of highlight may depend on a number of factors—such asthe relative of amount of time the system spends highlighting versus theamount of time spent illuminated the remainder of the image.

FIG. 3D depicts one embodiment of a control method 300 for formingand/or rendering a highlight feature which may comprise a portion of animage frame and/or video data. At 302, the controller may receiveimage/video data comprising a portion of the image/video data that is afeature to be highlighted within an image frame(s) or a portion of thevideo data. At 304, the controller may send control signals to theanalog modulator (which may be the first modulator layer/stage or othermodulator layer/stage). These control signals may induce the analogmirrored elements to focus, or otherwise project, a good portion of thelight from the light source onto second, or other, modulatorlayer/stage.

The amount of light focused by the analog modulator may vary accordingto the image to be rendered. In some cases, the controller may directthat all of the available light is to be focused and/or modulated inorder to render the highlight. In other cases, the amount of lightdevoted to the highlight may be substantially less than 100% of theavailable light. In yet other cases, there may be a desired portion ofthe available light devoted to one or many highlights and some portionof the light devoted to other parts/portions of the image/video datathat may not be highlighted. It may suffice for purposes of the presentapplication that the projector system be able to dynamically allocate adesired amount and/or proportion of the available light in order torender/project highlight features.

The controller may send control signals to the second/other modulator tofurther modulate the light, so that the rendered and/or projected imageis sending a good portion of the light energy to the highlighted portionof the image and/or video data.

As is discussed, this focusing and/or projecting from the analog mirrorsmay be for a brief period of time—e.g., in a sub-frame of imagerendering and/or in some time multiplexed fashion. In this manner, thehighlighted portion may receive a good portion of the light energy sothat the highlighted portion is visibly highlighted by intended viewersof the image/video data.

As mentioned above, the previous manner to show portion 220 b as ahighlight might have been to have a constant light source outputting atits peak luminance—and focus the full luminance on the highlight, whilethrowing away excess light that is not needed or desired on other partsof the image. This, however, tends to waste the light energy of thedisplay system.

Embodiments Comprising MEMS Arrays

Conceptually, this time division multiplexing scheme may tend to workwell—as only a small percentage of the light energy is required for thehighlights. However, in the case in which the first (or early stage)modulator is a MEMS array, then it may be the case that there arecurrently no commercially available beam-steering MEMS devices withnearly enough mirrors (or at least at an affordable price). In order toilluminate small highlights in a given image, the optimal number mayapproach over 1500 mirrors. However, the largest current devices maytend to have on the order of approximately 100 mirrors to a few hundredmirrors.

To compensate for the desirability for additional mirrors for properhighlighting, several embodiments of the present application may affecta new scheme for projecting images (e.g., in particular, imagescomprising highlights). For example, several embodiments employ a formof time division multiplexing during a frame period to modulate thelight. As noted above, DMDs typically employ a form of pulse widthmodulation—thus, the light from the light source is usually required tobe constant during the entire frame period. As will be discussed furtherherein, with time division multiplexing, the projector system mayproduce a non-constant illumination.

Thus, several embodiments of the present application may steer the lightbeam on the modulators (e.g., modulation chips such as MEMS, analog DMDdevices and/or digital DMD devices)—only where and/or when needed. Inthe example of FIGS. 3A through 3C, it was seen that a time divisionmultiplexing scheme may split a frame period into a number ofsub-frames. In that example, it was depicted as three subframes T1, T2and T3; however, it will be appreciated that other frame subdivisionsmay be possible and the scope of the present application encompassesother subframe subdivision schemes. As will be discussed further herein,several embodiments may employ a different number of subframes—e.g., 2,4 or 16 subframes.

Multi-Modulation Projector Embodiments

While some embodiments of the present application may comprise a dualmodulator system, other systems having triple (or more) modulators mayalso suffice for purposes of the present application.

FIG. 4 is one multi-modulator system 400 comprising a light source 402a, illuminating a first light beam 404 a to a beamsplitter 405. Toprovide the highlight, a second light beam 404 b may illuminate a firstmodulator 403. First modulator 403 may be a MEMS array or some othersuitable faster switching set of elements. To create the second lightbeam 404 b, there may be an optional, additional light source 402 b—or apart of the first light beam 404 a may be split out to form second lightbeam 404 b in any manner known in the art.

Beamsplitter 405 may serve to combine the first and the second lightbeams to illuminate a second modulator 406. Second modulator 406 maycomprise either a MEMS array or a DMD device or any other suitablemodulator. Second modulator 406 may illuminate a third modulator 410(via, possibly, an intermediate optical system 408. Optical system 408may provide sufficient blurring or other condition of theillumination—such that the convolution of the light from the secondmodulator to third modulator is sufficient to project a suitable imageonto projector screen 414 (via, possibly, a projector optical system412).

FIG. 5 depicts yet another possible multi-modulator display system 500that may be suitable for the purposes of the present application. Lightsource 502 may illuminate a first light beam 504. Polarizer 505 mayapply a desired polarization to light beam 504. Light beam 504 may besplit by a polarizing beamsplitter 506 and create a second light beam508. Second light beam 508 may illuminate a first modulator 510—whichmay comprise a MEMS array or some other fast switching elements. Lightfrom first modulator 510 may illuminate a second modulator 512—which maycomprise a MEMS array or DMD device or any other suitable modulator. Thelight from the third modulator may be combined with beam 514 atbeamsplitter/combiner 516. Thereafter, the resulting light mayilluminate a third modulator 518—which may illuminate a projectionscreen 522 (via, possibly, projection optical system 520).

Time Division Multiplexing/Bit Sequence Embodiments

Normally, a typical DMD employs a single bit sequence per frame toobtain a certain bit per pixel (e.g., 16 bit/pixel) modulation. In manyembodiments, the bit sequence may be modified such that the higher orderbits are spread across the frame period, therefore, they may be repeatedmultiple times. For example, in one embodiment, the top bits (e.g., thetop 12 bits of 16 bits) may be repeated for each subframe. This wouldallow a pattern with the top 12 bits to repeat—e.g., 16 times (in a 1/16subframe subdivision embodiment). The lower significant bits wouldremain unaffected—e.g., spread across the entire frame period.

In one embodiment, it may be possible to have the beam steering device(e.g., mirrors or other elements)—e.g., the first modulator—switchquickly and/or at a desired rate (e.g., 10-100 microseconds). This maybe desirable—so as that the first modulator may switch in a “dark” timebetween sequence repeats. During such a dark time, the display systemmay not be outputting any light to be rendered and/or projected. Thismay help to avoid noticeable and/or undesirable visual effects.

In the case where the first modulator and/or beam steering device with alesser number of elements (e.g., 200 elements) would need to be able toaddress a greater number (e.g., 3200 or more) locations. FIG. 6 depictsa high level switching scheme 600 that matches the bit-sequencerepeating pattern. Pattern 602 depicts the time periods (e.g., 602 a and602 b) during which the bit sequence is repeating. Between this timeperiods is a period of dark time (603) between sequence repeats. As maybe seen in pattern 604, the first modulator is able to switch multipletimes (e.g., 604 a, 604 b, . . . , 604 n) during the entire period andthe dark time.

A detailed description of one or more embodiments of the invention, readalong with accompanying figures, that illustrate the principles of theinvention has now been given. It is to be appreciated that the inventionis described in connection with such embodiments, but the invention isnot limited to any embodiment. The scope of the invention is limitedonly by the claims and the invention encompasses numerous alternatives,modifications and equivalents. Numerous specific details have been setforth in this description in order to provide a thorough understandingof the invention. These details are provided for the purpose of exampleand the invention may be practiced according to the claims without someor all of these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

The invention claimed is:
 1. A projector display system, comprising: alight source; a first modulator including a plurality of first mirrors,wherein the first modulator is configured to receive an emitted lightfrom the light source and the plurality of first mirrors are configuredto modulate the emitted light; a second modulator including a pluralityof second mirrors, wherein the second modulator is configured to receivea modulated light from the first modulator and the plurality of firstmirrors are configured to modulate the modulated light; and a controlcircuit configured to: receive an image data including at least onehighlight feature, the highlight feature corresponding to a portion ofan image indicated by the image data, the highlight feature having aluminance not less than a highest luminance of a remainder of the image,control the first modulator in a first sub-frame period to direct theemitted light to a first subset of the plurality of second mirrors, andcontrol the first modulator in a second sub-frame period to direct theemitted light to a second subset of the plurality of second mirrors, thesecond subset being a smaller proportion of the plurality of secondmirrors than the first subset, thereby to render the highlight feature.2. The projector display system according to claim 1, wherein thecontrol circuit is configured to alternate between the first sub-frameperiod and the second sub-frame period a plurality of times within oneframe period.
 3. The projector display system according to claim 1,wherein the light source is at least one of a xenon lamp, an arc lamp, alaser, an array of lasers, or an array of solid-state light emitters. 4.The projector display system according to claim 1, wherein the pluralityof first mirrors is at least one of a MEMS array or a set ofcontrollable analog mirrors.
 5. The projector display system accordingto claim 1, wherein the plurality of second mirrors is at least one of aMEMS array, a DMD array, a set of controllable analog mirrors, or a setof controllable digital mirrors.
 6. The projector display systemaccording to claim 1, wherein a total number of first mirrors in theplurality of first mirrors is less than a total number of second mirrorsin the plurality of second mirrors.
 7. The projector display systemaccording to claim 6, wherein the total number of first mirrors isgreater than or equal to 100 and less than or equal to
 3000. 8. Theprojector display system according to claim 6, wherein the total numberof second mirrors is greater than or equal to 500,000.
 9. The projectordisplay system according to claim 1, further comprising a first opticalsystem configured to transfer the modulated light from the firstmodulator to the second modulator.
 10. The projector display systemaccording to claim 8, wherein the first optical system is configured toperform a predetermined point spread function of illumination onto thesecond modulator.
 11. The projector display system according to claim 1,further comprising a second optical system configured to focus aprojection light from the second modulator onto a screen.
 12. Theprojector display system according to claim 1, wherein the controlcircuit is further configured to: allocate a dark period within thefirst sub-frame period, wherein the light source does not output theemitted light during the dark period; and switch the first modulatorduring the dark period.
 13. A non-transitory computer-readable mediumstoring instructions that, when executed by a control circuit of aprojector display system comprising a light source, a first modulatorincluding a plurality of first mirrors, and a second modulator includinga plurality of second mirrors, cause the projector display system toperform operations comprising: receive an image data including at leastone highlight feature, the highlight feature corresponding to a portionof an image indicated by the image data, the highlight feature having aluminance not less than a highest luminance of a remainder of the image;control the first modulator in a first sub-frame period to direct anemitted light from the light source to a first subset of the pluralityof second mirrors; and control the first modulator in a second sub-frameperiod to direct the emitted light to a second subset of the pluralityof second mirrors, the second subset being a smaller proportion of theplurality of second mirrors than the first subset, thereby to render thehighlight feature.
 14. The non-transitory computer-readable mediumaccording to claim 13, the operations further comprising alternatingbetween the first sub-frame period and the second sub-frame period aplurality of times within one frame period.
 15. The non-transitorycomputer-readable medium according to claim 13, the operations furthercomprising transferring a modulated light from the first modulator tothe second modulator.
 16. The non-transitory computer-readable mediumaccording to claim 15, wherein transferring the modulated light includesperforming a predetermined point spread function of illumination ontothe second modulator.
 17. The non-transitory computer-readable mediumaccording to claim 13, the operations further comprising focusing aprojection light from the second modulator onto a screen.
 18. Aprojector display system, comprising: a plurality of color projectors,wherein respective ones of the plurality of color projectors correspondto a different color of light, and wherein respective ones of theplurality of color projectors comprise: a light source; a firstmodulator including a plurality of first mirrors, wherein the firstmodulator is configured to receive an emitted light from the lightsource and the plurality of first mirrors are configured to modulate theemitted light; a second modulator including a plurality of secondmirrors, wherein the second modulator is configured to receive amodulated light from the first modulator and the plurality of firstmirrors are configured to modulate the modulated light; and a controlcircuit configured to: receive an image data including at least onehighlight feature, the highlight feature corresponding to a portion ofan image indicated by the image data, the highlight feature having aluminance not less than a highest luminance of a remainder of the image,control the first modulator in a first sub-frame period to direct theemitted light to a first subset of the plurality of second mirrors,control the first modulator in a second sub-frame period to direct theemitted light to a second subset of the plurality of second mirrors, thesecond subset being a smaller proportion of the plurality of secondmirrors than the first subset, thereby to render the highlight feature.19. The projector display system according to claim 18, wherein theplurality of color projectors is a first color projector correspondingto a red color light, a second color projector corresponding to a greencolor light, and a third color projector corresponding to a blue colorlight.
 20. The projector display system according to claim 18, wherein,in respective ones of the plurality of color projectors, the lightsource is at least one of a xenon lamp, an arc lamp, a laser, an arrayof lasers, or an array of solid-state light emitters.